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Hui-Ying X.,Zhejiang Shuren University | Jian-Wei Z.,Zhejiang University | Gui-Xiang H.,Zhejiang University | Wei W.,Zhenhai Environmental Monitoring Station
Chemosphere | Year: 2010

Polychlorinated diphenyl ethers (PCDEs) are a group of important persistent organic pollutants. In the present study, geometrical optimization and electrostatic potential calculations have been performed for all 209 PCDE congeners at the HF/6-31G* level of theory. A number of statistically-based parameters have been obtained. Linear relationships between gas-chromatographic relative retention time (RRT), n-octanol/water partition coefficient (logKOW), 298K supercooled liquid vapour pressures (logpL), aqueous solubilities (logSw,L) and the immunotoxicity values (logED50) of PCDEs and the structural descriptors have been established by multiple linear regression method. The result shows that the quantities derived from electrostatic potential Vs,min,∑Vs+,Vs,av-,Π,σtot2,σ+2,ν, and Nv+, together with the number of the chlorine atoms on the two phenyl rings (NCl) can be well used to express the quantitative structure-property (activity) relationships of PCDEs. Good predictive capabilities have also been demonstrated by leave-group(1/5)-out cross-validation and external test set. Based on these equations, the predicted values have been presented for those PCDE congeners whose experimentally determined physico-chemical properties are unavailable. © 2010 Elsevier Ltd. Source


Xu H.,Zhejiang Shuren University | Wang W.,Zhenhai Environmental Monitoring Station | Zou J.,Zhejiang University
Acta Chimica Sinica | Year: 2013

Intermolecular interactions between PH2X (X=H, F, Cl, Br) and five-member heterocyclic compounds (pyrrole, furan, thiophene) were calculated by using MP2/aug-cc-pVDZ quantum chemical method, and the interaction energies were corrected with BSSE (basis set superposition error) by complete counterpoise correction method. On the basis of MP2/aug-cc-pVDZ optimized geometries, the second-order perturbation stabilization energies (ΔE2) and AIM properties were calculated using the NBO (natural bond orbital) program in Gaussian 03 and AIM 2000 program, respectively. In order to further understand this type of interaction, graphical analyses for representative systems were performed using the reduced density gradient (RDG) color-filled isosurface map and the electronic density difference map. It has been showed that the P-H⋯π hydrogen bonding interaction is formed between PH3 and three five-member heterocyclic compounds, and the pnicogen bonding interactions between PH2X (X=F, Cl, Br) and five-member heterocyclic compounds. There exist two types of pnicogen bonding interactions (π- and n-types) in these complexes, and the stabilities of the π-type pnicogen bonded complexes are stronger than those of the n-type ones. Moreover, the interaction energies have been found to correlate closely with the angle between P-X vector and the direction vector of P atom to the heterocyclic centroid. For comparison, intermolecular interactions between PCl3 and the three kinds of heterocyclic compounds were also studied. It has been showed that three positive electrostatic potential areas (or "σ-hole") are presented at phosphorus atom end along the Cl-P bond in PCl3 molecule, so the complexes with multi-pnicogen-bonding can be formed between PCl3 and the heterocyclic compounds. Through atom in molecule (AIM) analysis, it has been disclosed that the nature of all the pnicogen bonding interactions belongs to the closed-shell electrostatic interactions, and the stabilities of the complexes are correlated positively with the electron densities in the bond critical points (BCPs). RDG graphical analyses are performed to visualize the positions and strengths of the pnicogen bonding. DDF analyses are also done, and indicating that electron density is reduced at phosphorus atom end and increased around the P-X axis and five-member heteroc yclic molecule because of the pnicogen bonding interaction, thus the underlying rearrangement of the electron densities is intuitively reflected. © 2013 Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences. Source


Wang W.,Zhenhai Environmental Monitoring Station | Xu H.-Y.,Zhejiang Shuren University
Jiegou Huaxue | Year: 2010

Based on QSPR of alcohol and ether organic compounds in water, geometrical optimization and electrostatic potential calculations were performed at the HF/6-31G* level for 73 alcohol and ether organic compounds. Linear relationships between infinite dilution activity coefficient (lnγ∞) of alcohols and ethers in water and theoretical descriptors of the molecular structure were established by multiple regression method. The result shows that the parameters derived from molecular electrostatic potential together with molecular surface area can be preferably used to express the quantitative structure-lnγ∞ relationship of alcohols and ethers in water. This reveals that this model has good predictive capabilities (RCV = 0.969). The molecular electrostatic potential has also been proved to have the general applicability in QSPR model of alcohol and ether organic compounds about γ ∞ in water. The QSPR model established may provide a new powerful method for predicting γ∞ of organic compounds in aqueous systems. Source


Zhu J.-Q.,Zhejiang Shuren University | Wang W.,Zhenhai Environmental Monitoring Station | Xu H.-Y.,Zhejiang Shuren University
Advanced Materials Research | Year: 2013

Based on quantitative structure-property relationship (QSPR) of organic compounds, geometrical optimization and quantum chemical parameter calculations have been performed at the B3LYP/6-31G&z.ast; level of theory for 75 polychlorinated naphthalenes (PCNs). A number of statistically-based parameters have been obtained. Relationship between the physicochemical properties of polychlorinated naphthalene compounds (n-octanol/air partition coefficient, sub-cooled liquid vapor pressure, water solubility) and the structural descriptors have been established by multiple linear regression (MLR) method. The results show that the molecular volume (Vmc), dipolar moment (μ), and the energy of lowest unoccupied molecular orbital (ELUMO), together with the quantity derived from electrostatic potential (σVs -) can be well used to express the quantitative structure-property relationships of polychlorinated naphthalene compounds. The models constructed have good robustness and high predictive capability. © (2013) Trans Tech Publications, Switzerland. Source


Xu H.-Y.,Zhejiang Shuren University | Zhu J.-Q.,Zhejiang Shuren University | Wang W.,Zhenhai Environmental Monitoring Station | Lu Y.,Zhejiang Shuren University | Xu X.-L.,Zhejiang Shuren University
Advanced Materials Research | Year: 2014

To characterize the concentration levels of PFOS and PFOA in the Qiantang River waters of China, 12 water samples were collected in May 2013 and analyzed. The concentrations of PFOS and PFOA were from n.d to 0.798 ng/L and from 65.9 to 102.4 ng/L, respectively. PFOS has been observed at a low concentration in these samples, while PFOA was detected in 100% of the samples with higher PFOA concentrations. PFOA concentrations were far higher than those of PFOS in all the samples, which subjected to be influenced by the inflows of the chemicals from a lot of the textile dyeing industry along the south bank of the river. Although the PFOS and PFOA concentration in Qiantang River water samples did not exceeded this provisional health advisory level (limit) established by the United States Environmental Protection Agency for PFOS and PFOA in drinking waters of 200 ng/L and 400 ng/L respectively, continued exposure to even relatively low PFOS and PFOA concentrations in drinking water may increase the risk of health effects. © (2014) Trans Tech Publications, Switzerland. Source

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